1. Field of the Invention
The present invention relates to a method and apparatus for determining elementary circuits and initial values of flows in a pipe network before applying the Hardy Cross method or the like to the pipe network to compute the flow of each pipe.
2. Description of the Related Art
Computation of flows in a network of pipes has been performed in such cases as new pipes are installed or stable supply are considered in water or gas networks. Similar computation has also been carried out in electric distribution networks.
A method for such computation using the Hardy Cross method is described, for example, on pages 427-438 in "Fluid Mechanics", V. L. Streeter, et al., McGraw-Hill Book Co., 1985. In this method, an engineer must divide a pipeline network into a plurality of elementary circuits, and then designate an initial flow for each pipe of the network at the initial stage of the computation. Once these initial setting has been completed, the Hardy Cross method which has been programmed for numerical solution on a digital computer can accomplish the computation, and outputs the flow distribution of the network. Here, an elementary circuit refers to a loop or a pseudo loop described in the Streeter reference mentioned above.
Determination of the elementary circuits and initial values, however, requires manual operation. This presents a problem because determining the elementary circuits in a complicated network of pipes is a very time consuming process. In addition, wasteful computations are often involved in the process owing to engineer's errors, such as selecting an unnecessary elementary circuit.
Likewise, since the initial values of flows are set by an intuition of an engineer, the increasing number of iteration of computation will be required unless the initial setting is appropriate. This also presents a problem in that it takes a long time to complete the computation.